import pygame


class Ship:
    def __init__(self, screen, settings):
        self.screen = screen
        self.settings = settings

        # 加载飞船图像，获取其外接矩形
        self.image = pygame.image.load('images/ship.bmp')
        self.rect = self.image.get_rect()
        self.screen_rect = screen.get_rect()

        # 放在屏幕底部中央
        self.rect.centerx = self.screen_rect.centerx
        self.rect.bottom = self.screen_rect.bottom
        self.center = float(self.rect.centerx)

        # 移动标志
        self.moving_left = False
        self.moving_right = False

    def update(self, screen):
        if self.moving_left and self.rect.left > 0:
            self.center -= self.settings.ship_speed_factor
        if self.moving_right and self.rect.right < self.settings.screen_width:
            self.center += self.settings.ship_speed_factor
        self.rect.centerx = self.center

    def blitme(self):
        self.screen.blit(self.image, self.rect)

    def center_ship(self):
        self.center = self.screen_rect.centerx